The present invention relates to an apparatus for melting and applying a meltable adhesive. Such an apparatus is particularly useful in combination with edge gluing machines in which the gluing operation takes place by continuously feeding the work pieces through the edge gluing machine. U.S. Pat. Nos. 4,178,876 and 4,232,064 (both issued to W. Nicklas et al) are based on German Patent Publication 2,731,799 and disclose prior art structures for the melting and applying of a meltable adhesive. In the prior art the meltable adhesive is used in the form of cylindrical cartridges which are introduced into a melting chamber in which they are pressed against a melting wall by means of a feed advance piston. Such devices are customarily equipped with an adhesive application device to which the molten adhesive is supplied for application to the narrow edge of a work piece.
The meltable adhesive cartridges or units are supplied by a magazine through a supply opening in the melting chamber, whereby a closure slide which is connected with the feed advance piston, closes the magazine during the feed advance stroke of the feed advance piston.
Meltable adhesives in this context are considered to include all synthetic material adhesives which are solid at room temperature and which are heated to liquify the adhesive for its application to the work piece. Further, these adhesives solidify substantially instantly when the work pieces are joined.
Such adhesives are originally commercially sold as a granular material. It is therefore desirable to employ the granular material directly in a melting and applying apparatus of the type described above. This would avoid the formation of cartridges of the granular material. However, difficulties have been encountered in such an endeavor because the granular material would be pressed back into the supply container as a result of the feed advance stroke, whereby the feed advance piston in the melting chamber could be jammed.